Williams, making her first appearance in Strasbourg, was never at her best against Rezai and was punished for a sloppy display with a 64 64 defeat. The Frenchwoman on the other hand played some sparkling tennis on her way to avenging the pair's only previous Sony Ericsson WTA Tour meeting; a straight sets victory for Williams at Amelia Island in April. Next up for the 20-year-old from St. Etienne is experienced American Meghann Shaughnessy, who overcame Russian qualifier Ekaterina Afinogenova, 61 63.

"I don't know if she thought she played well or not but I think I had a very good match today. I've been working very hard lately," Rezai said. "and my strategy today was to move her from side to side, because she's so tall. The victory today proves to me that I can beat these higher-ranked players, so it's a special day for me."

After a first round bye, Russia's Dementieva got her campaign underway on Wednesday, taking on Croatia's Kostanic Tosic for a place in the quarterfinals. The 25-year-old Muscovite has had an inconsistent year to date, reaching the semifinals in Tokyo [Pan Pacific], but also falling before the quarterfinals in five other tournaments.

Dementieva started slowly against the 25-year-old from Split, missing a few routine shots early on, but did just enough to win the opening set. The 2004 Roland Garros runner-up improved in the second, racing into a 5-1 lead and despite a late wobble, recorded a straightforward 63 63 victory 77 minutes.

"It's never easy to play your first match at a tournament. I'd never even practiced on the centre court before," Dementieva said. "so it took me a couple of games to get my rhythm. She's a good clay-courter, playing with a lot of slice, and she's a left-hander, which you don't play too often. I'm hoping to win some more matches here, because it's important to have a good preparation for Roland Garros."

World No.15 Schnyder has been in tremendous form since the clay court season kicked off in mid-April, reaching the semifinals in Rome and the quarterfinals a week before in Berlin. With Roland Garros looming on the horizon, the No.3 seed will be delighted with how she is playing, producing a dominant display on Wednesday to send American teenager King packing, 64 61.

"It was definitely harder than in the first round," Schnyder said. "but I still felt like I was in control of the match. I was using a lot of slice and some drop shots, which she struggled with, so it was another good match for me – I'm feeling good about my game at the moment."

Lying in wait for Swiss No.2 Schnyder will be Alona Bondarenko, who came out on top in one of the day's more entertaining matches against Latvian qualifier Anastasija Sevastova. After capturing a close opening set the 22-year-old from Ukraine looked all set for a comfortable passage into the quarterfinals, however, the 17-year-old Latvian had other ideas, upping her game and taking the match into a deciding set.

The third set was a nervous affair, with players trading breaks before the match headed into a decisive tie-break. There was little to chose between the two even then, although ultimately experience triumphed over youth, with Bondarenko completing a 64 36 76(5) victory.

The only other seed on display in Istanbul was Poland's Agnieszka Radwanska, who looked in great touch on her way to a crushing 61 60 defeat of Italy's Romina Oprandi. The No.7 seed now goes on to meet No.1 seed Maria Sharapova in the next round, with a semifinal place at stake. The day's only other match saw Catalina Castaño bounce back from the loss of the first set, to book a quarterfinal meeting against No.2 seed Dementieva with a 46 75 61 win.

The experienced Colombian Castaño was also in doubles action, teaming up with America's Neha Uberoi to defeat the Russian-Georgian partnership of Afinogenova and Anna Tatishvili, 57 63 103. The other two teams to make it through to Thursday's quarterfinals were Mervana Jugic-Salkic and Oprandi and Belarusian duo Tatiana Poutchek and Anastasiya Yakimova. (WTA)